Light source device and subject observation apparatus as well as light source control method

Abstract

A light source device includes: excitation light sources configured to emit a plurality of excitation light including mutually different spectra; wavelength converting members configured to wavelength-convert the excitation light emitted from the excitation light sources into light having mutually different spectra and configured to be disposed in a common application region of the excitation light; and a light source control unit configured to switch a combination of the excitation light sources that are lighted among the excitation light sources based on the observation mode including a normal light observation mode and a special light observation mode to highlight a particular observation target input to an input unit, wherein light emitted from the wavelength converting members is used as illumination light, and the illumination light corresponding to the observation modes is emitted from a same emitting portion.

What is claimed is: 
     
       1. A light source device comprising:
 excitation light sources configured to emit a plurality of excitation light including mutually different spectra; 
 wavelength converters configured to wavelength-convert the plurality of excitation light emitted from the excitation light sources into light having mutually different spectra and configured to be disposed in a common application region of the plurality of excitation light; 
 an input configured to input observation modes including a normal light observation mode and a special light observation mode to highlight a particular observation target; and 
 a light source controller configured to switch a combination of the excitation light sources that are lighted among the excitation light sources based on the observation mode input to the input, 
 wherein light emitted from the wavelength converter is used as illumination light, and the illumination light corresponding to the observation modes is emitted from a same emitting portion, 
 wherein the excitation light sources further comprise an optical coupler configured to couple the plurality of excitation light, and 
 wherein the wavelength converters are separated from the excitation light sources by more than a length of the optical coupler. 
 
     
     
       2. The light source device according to  claim 1 , wherein
 the excitation light sources comprise:
 a first excitation light source configured to emit a first excitation light including a first spectrum; and 
 a second excitation light source configured to emit a second excitation light including a second spectrum different from the first spectrum, and 
 
 the light source controller is configured to switch between the lighting of the first excitation light source alone and simultaneous lighting of the first and second excitation light sources based on the observation mode input to the input. 
 
     
     
       3. The light source device according to  claim 2 , wherein the wavelength converters comprise:
 a first wavelength converter configured to emit light having a third spectrum that is longer in wavelength than the first spectrum and that is different from the second spectrum when the first excitation light is applied; and 
 a second wavelength converter configured to emit light having a fourth spectrum that is longer in wavelength than the second spectrum and that is different from the first and third spectra when the second excitation light is applied. 
 
     
     
       4. The light source device according to  claim 3 , wherein
 when the special light observation mode is input to the input, the light source controller lights the first excitation light source alone to emit first illumination light including the first and third spectra, and 
 when the normal light observation mode is input to the input, the light source controller simultaneously lights the first and second excitation light sources to emit second illumination light including the first to fourth spectra. 
 
     
     
       5. The light source device according to  claim 4 , wherein in a wavelength region located in the vicinity of a peak of light absorption of the particular observation target in a visible light region, the first illumination light has a higher spectral intensity than in a low-light-absorption wavelength region located apart from the peak of the light absorption. 
     
     
       6. The light source device according to  claim 5 , wherein
 the particular observation target includes peaks of the light absorption, and 
 in wavelength regions located in the vicinity of the mutually different peaks of light absorption, the first spectrum and the third spectrum have higher spectral intensities than in low-light-absorption wavelength regions located apart from the peaks of the light absorption. 
 
     
     
       7. The light source device according to  claim 6 , wherein
 the particular observation target is hemoglobin in blood, and 
 the first and third spectra have higher spectral intensities in wavelength regions of 400 nm to 440 nm and 525 nm to 555 nm, respectively, in the vicinity of the peak of the light absorption of the hemoglobin. 
 
     
     
       8. The light source device according to  claim 5 , wherein in the low-light-absorption wavelength regions located apart from the peak of the light absorption of the particular observation target, the first illumination light includes wavelength lacking region in which spectral intensity is less than or equal to a predetermined value compared to the maximum intensity of the light emission spectrum of the first illumination light. 
     
     
       9. The light source device according to  claim 8 , wherein the wavelength lacking regions are configured so that the spectral intensity is less than or equal to one twentieth of the maximum intensity of the light emission spectrum in the first illumination light. 
     
     
       10. The light source device according to  claim 8 , wherein the first illumination light includes a first wavelength lacking region in a wavelength region between the first spectrum and the third spectrum. 
     
     
       11. The light source device according to  claim 10 , wherein the second illumination light includes the second spectrum in the first wavelength lacking region. 
     
     
       12. The light source device according to  claim 8 , wherein the first illumination light includes a second wavelength lacking region in a wavelength region on the longer wavelength side than the third spectrum. 
     
     
       13. The light source device according to  claim 4 , wherein the second illumination light is a white light. 
     
     
       14. The light source device according to  claim 3 , wherein the second wavelength converter hardly wavelength-converts the first excitation light, and includes at least one of transmitting and scattering properties. 
     
     
       15. The light source device according to  claim 3 , wherein the first wavelength converter is a green fluorescent material having a peak of a light emission spectrum in a wavelength region of 500 nm to 580 nm. 
     
     
       16. The light source device according to  claim 3 , wherein the second wavelength converter is a red fluorescent material having a peak of a light emission spectrum in a wavelength region of 600 nm to 750 nm. 
     
     
       17. The light source device according to  claim 3 , wherein the second wavelength converter is a yellow fluorescent material having a peak of a light emission spectrum in a wavelength region of 550 nm to 650 nm. 
     
     
       18. The light source device according to  claim 3 , further comprising:
 a third excitation light source configured to emit third excitation light having a fifth spectrum different from the first to fourth spectra, 
 wherein the wavelength converters further comprises a third wavelength converter configured to emit light having a sixth spectrum that is longer in wavelength than the fifth spectrum and that is different from the first to fourth spectra when the third excitation light is applied. 
 
     
     
       19. The light source device according to  claim 18 , wherein
 when the special light observation mode is input to the input, the light source controller lights the first excitation light source alone to emit first illumination light including the first and third spectra, and 
 when the normal light observation mode is input to the input, the light source controller simultaneously lights the third excitation light source in addition to the first and second excitation light sources to emit second illumination light including the first to sixth spectra. 
 
     
     
       20. The light source device according to  claim 19 , wherein
 the first illumination light includes, in a wavelength region between the first spectrum and the third spectrum, a first wavelength lacking region in which spectral intensity is less than or equal to one twentieth of the maximum intensity of the light emission spectrum of the first illumination light, and 
 the sixth spectrum in the second illumination light exists in the first wavelength lacking region. 
 
     
     
       21. The light source device according to  claim 18 , wherein the fifth spectrum exists in a near-ultraviolet wavelength region. 
     
     
       22. The light source device according to  claim 2 , wherein the first spectrum exists in a wavelength region of 400 nm to 430 nm. 
     
     
       23. The light source device according to  claim 2 , wherein the second spectrum exists in a wavelength region of 430 nm to 460 nm. 
     
     
       24. The light source device according to  claim 1 , wherein
 the excitation light sources include:
 a first excitation light source configured to emit first excitation light including a first spectrum; 
 a second excitation light source configured to emit second excitation light including a second spectrum different from the first spectrum; and 
 a third excitation light source configured to emit third excitation light having a fifth spectrum different from the first and second spectra, 
 
 the wavelength converters comprise:
 a first wavelength converter configured to emit light having a third spectrum that is longer in wavelength than the first spectrum and that is different from the second to fifth spectra when the first excitation light is applied; 
 a second wavelength converter configured to emit light having a fourth spectrum that is longer in wavelength than the second spectrum and that is different from the first, third, and fifth spectra when the second excitation light is applied; and 
 a third wavelength converter configured to emit light having a sixth spectrum that is longer in wavelength than the fifth spectrum and that is different from the first to fourth spectra when the third excitation light is applied, and 
 
 the light source controller is configured to switch a combination of the excitation light sources that are lighted among the first to third excitation light sources based on the observation mode input to the input. 
 
     
     
       25. The light source device according to  claim 24 , wherein
 when the special light observation mode is input to the input, the light source controller simultaneously lights the first and third second excitation light sources to emit first illumination light including the first, third, fifth, and sixth spectra, and 
 when the normal light observation mode is input to the input, the light source controller simultaneously lights the first to third excitation light sources to emit second illumination light including the first to sixth spectra. 
 
     
     
       26. The light source device according to  claim 25 , wherein in wavelength regions located in the vicinity of different peaks among peaks of light absorption of the particular observation target in a visible light region, the first, third, and sixth spectra have higher spectral intensities than in low-light-absorption wavelength regions located apart from the peaks of the light absorption, respectively. 
     
     
       27. The light source device according to  claim 24 , wherein
 the input is configured to input a normal light observation mode, a first special light observation mode to highlight a first particular observation target, and a second special light observation mode to highlight a second particular observation target different from the first particular observation target, 
 when the first special light observation mode is input to the input, the light source controller lights the first excitation light source alone to emit first illumination light including the first and third spectra, 
 when the normal light observation mode is input to the input, the light source controller simultaneously lights the first and second excitation light sources to emit second illumination light including the first to fourth spectra, and 
 when the second special light observation mode is input to the input, the light source controller lights the third excitation light source alone to emit third illumination light including the fifth and sixth spectra. 
 
     
     
       28. The light source device according to  claim 27 , wherein in a wavelength region located in the vicinity of a peak of light absorption of the second particular observation target, the third illumination light has a higher spectral intensity than in a low-light-absorption wavelength region located apart from the peak of the light absorption of the second particular observation target. 
     
     
       29. A subject observation apparatus comprising:
 the light source device according to  claim 1 , the illumination light emitted from the light source device being applied to a subject; and 
 an image acquiring unit configured to acquire image information regarding the subject. 
 
     
     
       30. A light source control method comprising:
 inputting one of observation modes including a normal light observation mode and a special light observation mode to highlight a particular observation target; 
 switching a combination of excitation light sources that are lighted among excitation light sources based on the input observation mode information; 
 emitting excitation light having mutually different spectra from the lighted excitation light sources and then applying the excitation light to wavelength converters; and 
 using light emitted from the wavelength converters as illumination light, and emitting the illumination light corresponding to the observation modes from a same emitting portion, 
 wherein the excitation light sources further comprise an optical coupler configured to couple the plurality of excitation light, and 
 wherein the wavelength converters are separated from the excitation light sources by more than a length of the optical coupler. 
 
     
     
       31. The light source control method according to  claim 30 , wherein
 the excitation light sources comprise:
 a first excitation light source configured to emit first excitation light including a first spectrum; and 
 a second excitation light source configured to emit second excitation light including a second spectrum different from the first spectrum, 
 
 the light source controller is configured to switch between the lighting of the first excitation light source alone and simultaneous lighting of the first and second excitation light sources based on the observation mode input to the input, 
 the wavelength converters comprise:
 a first wavelength converter configured to emit light having a third spectrum that is longer in wavelength than the first spectrum and that is different from the second spectrum when the first excitation light is applied; and 
 a second wavelength converter configured to emit light having a fourth spectrum that is longer in wavelength than the second spectrum and that is different from the first and third spectra when the second excitation light is applied, 
 
 in the special light observation mode, the first excitation light source alone is lighted to emit first illumination light including the first and third spectra from the wavelength converters, and 
 in the normal light observation mode, the first and second excitation light sources are simultaneously lighted to emit second illumination light including the first to fourth spectra from the wavelength converters. 
 
     
     
       32. The light source control method according to  claim 31 , wherein
 the excitation light sources further includes a third excitation light source configured to emit third excitation light having a fifth spectrum different from the first to fourth spectra, 
 the wavelength converters further comprise a third wavelength converter configured to emit light having a sixth spectrum that is longer in wavelength than the fifth spectrum and that is different from the first to fourth spectra when the third excitation light is applied, and 
 in a second special light observation mode to highlight a second particular observation target different from the particular observation target, the third excitation light source alone is lighted to emit third illumination light including the fifth and sixth spectra.